US2025317168A1PendingUtilityA1
Method and apparatus for transmission based on multiple input and multiple output in line-of-sight channel environment
Assignee: ELECTRONICS & TELECOMMUNICATIONS RES INSTPriority: Apr 9, 2024Filed: Dec 26, 2024Published: Oct 9, 2025
Est. expiryApr 9, 2044(~17.7 yrs left)· nominal 20-yr term from priority
H04B 7/0639H04B 7/0617H04B 7/0456H04B 7/0478
61
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Claims
Abstract
A method of a first communication node may comprise: obtaining a channel matrix or a plurality of phase vectors based on predetermined line-of-sight multiple input multiple output (LOS MIMO) channel configuration information; determining a precoding matrix satisfying a first condition and a second condition using the channel matrix or the plurality of phase vectors; and transmitting data to a second communication node including a second antenna array by performing beamforming at the first communication node including a first antenna array based on the precoding matrix, wherein the first antenna array includes N elements, the second antenna array includes L elements, and each of L and N is a natural number greater than or equal to 2.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A method of a first communication node, comprising:
obtaining a channel matrix or a plurality of phase vectors based on predetermined line-of-sight multiple input multiple output (LOS MIMO) channel configuration information; determining a precoding matrix satisfying a first condition and a second condition using the channel matrix or the plurality of phase vectors; and transmitting data to a second communication node including a second antenna array by performing beamforming at the first communication node including a first antenna array based on the precoding matrix, wherein the first antenna array includes N elements, the second antenna array includes L elements, and each of L and N is a natural number greater than or equal to 2.
2 . The method according to claim 1 , wherein the precoding matrix is calculated using a Hermitian transpose of the channel matrix, and the precoding matrix is expressed as Equation 1-A using the channel matrix,
P
=
1
N
·
1
L
·
H
H
,
[
Equation
1
-
A
]
wherein P represents the precoding matrix, H represents the channel matrix, and H H represents the Hermitian transpose of H.
3 . The method according to claim 1 , wherein the precoding matrix is calculated using the plurality of phase vectors, and the precoding matrix is expressed as Equation 1-B using the plurality of phase vectors,
[
Equation
1
-
B
]
P
=
1
N
·
1
L
·
[
exp
(
j
·
π
·
∅
1
)
exp
(
j
·
π
·
∅
2
)
…
exp
(
j
·
π
·
∅
L
)
]
,
wherein P represents the precoding matrix, and Ø 1 , Ø 2 , . . . , and Ø L represent the plurality of phase vectors.
4 . The method according to claim 1 , wherein the precoding matrix includes L precoding vectors, the first condition is satisfied when elements of a first precoding vector and elements of a second precoding vector among the L precoding vectors are symmetrical to each other, the precoding matrix is expressed as Equation 1-C, and each of the first precoding vector and the second precoding vector is expressed as Equation 1-D,
P
=
[
p
1
p
2
…
p
L
]
[
Equation
1
-
C
]
p
1
+
k
=
[
v
1
v
2
…
v
N
-
1
v
N
]
T
,
[
Equation
1
-
D
]
p
L
-
k
=
[
v
N
v
N
-
1
…
v
2
v
1
]
T
(
k
=
0
,
1
,
…
,
⌈
L
/
2
⌉
-
1
)
,
wherein P represents the precoding matrix, p 1 p 2 . . . p L represent the L precoding vectors, p 1+k represents the first precoding vector, p L−k represents the second precoding vector, and ┌x┐ is a smallest integer equal to or greater than x.
5 . The method according to claim 1 , wherein the precoding matrix includes L precoding vectors, the second condition is satisfied when L is odd and elements of a middle precoding vector located in a middle of the L precoding vectors are symmetrical to each other, and the middle precoding vector is expressed as Equation 1-E,
p
L
-
k
=
[
v
N
v
N
-
1
…
v
2
v
1
]
T
[
Equation
1
-
E
]
v
1
=
v
N
,
v
2
=
v
N
-
1
,
…
,
v
⌈
L
/
2
⌉
-
1
=
v
⌈
L
/
2
⌉
+
1
,
wherein p ┌L/2┐ represents the middle precoding vector, and └x┘ is a largest integer equal to or less than x.
6 . The method according to claim 1 , wherein the transmitting of the data to the second communication node comprises:
transmitting a pilot signal to the second communication node; receiving, from the second communication node, feedback information including information of a precoding matrix for a channel state between the first communication node and the second communication node; confirming the precoding matrix included in a codebook using the feedback information; and transmitting the data to the second communication node by performing beamforming based on the precoding matrix included in the codebook.
7 . A method of a second communication node, comprising:
receiving a pilot signal from a first communication node; performing an operation of estimating a channel between the first communication node and the second communication node based on the pilot signal to obtain line-of-sight multiple input multiple output (LOS MIMO) channel information; determining a first precoding matrix based on the LOS MIMO channel information in a codebook including two or more precoding matrixes that satisfy a first condition and a second condition; and transmitting feedback information including information of the first precoding matrix to the first communication node.
8 . The method according to claim 7 , wherein the first precoding matrix includes L precoding vectors, the first condition is satisfied when elements of a first precoding vector and elements of a second precoding vector among the L precoding vectors are symmetrical to each other, L is a natural number equal to or greater than 2, the first precoding matrix is expressed as Equation 2-A, and each of the first precoding vector and the second precoding vector is expressed as Equation 2-B,
P
=
[
p
1
p
2
…
p
L
]
,
[
Equation
2
-
A
]
p
1
+
k
=
[
v
1
v
2
…
v
N
-
1
v
N
]
T
,
[
Equation
2
-
B
]
p
L
-
k
=
[
v
N
v
N
-
1
…
v
2
v
1
]
T
(
k
=
0
,
1
,
…
,
⌈
L
/
2
⌉
-
1
)
,
wherein P represents the first precoding matrix, p 1 p 2 . . . p L represent the L precoding vectors, p 1+k represents the first precoding vector, and p L−k represents the second precoding vector.
9 . The method according to claim 7 , wherein the first precoding matrix includes L precoding vectors, the second condition is satisfied when L is odd and elements of a middle precoding vector located in a middle of the L precoding vectors are symmetrical to each other, L is a natural number equal to or greater than 2, and the middle precoding vector is expressed as Equation 2-C,
p
L
-
k
=
[
v
N
v
N
-
1
…
v
2
v
1
]
T
[
Equation
2
-
C
]
v
1
=
v
N
,
v
2
=
v
N
-
1
,
…
,
v
⌈
L
/
2
⌉
-
1
=
v
⌈
L
/
2
⌉
+
1
,
wherein p ┌L/2┐ represents the middle precoding vector.
10 . A first communication node comprising at least one processor, wherein the at least one processor causes the first communication node to perform:
obtaining a channel matrix or a plurality of phase vectors based on predetermined line-of-sight multiple input multiple output (LOS MIMO) channel configuration information; determining a precoding matrix satisfying a first condition and a second condition using the channel matrix or the plurality of phase vectors; and transmitting data to a second communication node including a second antenna array by performing beamforming at the first communication node including a first antenna array based on the precoding matrix, wherein the first antenna array includes N elements, the second antenna array includes L elements, and each of L and N is a natural number greater than or equal to 2.
11 . The first communication node according to claim 10 , wherein the precoding matrix is calculated using a Hermitian transpose of the channel matrix, and the precoding matrix is expressed as Equation 3-A using the channel matrix,
P
=
1
N
·
1
L
·
H
H
,
[
Equation
3
-
A
]
wherein P represents the precoding matrix, H represents the channel matrix, and H H represents the Hermitian transpose of H.
12 . The first communication node according to claim 10 , wherein the precoding matrix is calculated using the plurality of phase vectors, and the precoding matrix is expressed as Equation 3-B using the plurality of phase vectors,
[
Equation
3
-
B
]
P
=
1
N
·
1
L
·
[
exp
(
j
·
π
·
∅
1
)
exp
(
j
·
π
·
∅
2
)
…
exp
(
j
·
π
·
∅
L
)
]
,
wherein P represents the precoding matrix, and Ø 1 , Ø 2 , . . . , and Ø L represent the plurality of phase vectors.
13 . The first communication node according to claim 10 , wherein the precoding matrix includes L precoding vectors, the first condition is satisfied when elements of a first precoding vector and elements of a second precoding vector among the L precoding vectors are symmetrical to each other, the precoding matrix is expressed as Equation 3-C, and each of the first precoding vector and the second precoding vector is expressed as Equation 3-D,
P
=
[
p
1
p
2
…
p
L
]
,
[
Equation
3
-
C
]
p
1
+
k
=
[
v
1
v
2
…
v
N
-
1
v
N
]
T
,
[
Equation
3
-
D
]
p
L
-
k
=
[
v
N
v
N
-
1
…
v
2
v
1
]
T
(
k
=
0
,
1
,
…
,
⌈
L
/
2
⌉
-
1
)
,
wherein P represents the precoding matrix, p 1 p 2 . . . p L represent the L precoding vectors, p 1+k represents the first precoding vector, p L−k represents the second precoding vector, and ┌x┐ is a smallest integer equal to or greater than x.
14 . The first communication node according to claim 10 , wherein the precoding matrix includes L precoding vectors, the second condition is satisfied when L is odd and elements of a middle precoding vector located in a middle of the L precoding vectors are symmetrical to each other, and the middle precoding vector is expressed as Equation 3-E,
p
L
-
k
=
[
v
N
v
N
-
1
…
v
2
v
1
]
T
[
Equation
3
-
E
]
v
1
=
v
N
,
v
2
=
v
N
-
1
,
…
,
v
⌈
L
/
2
⌉
-
1
=
v
⌈
L
/
2
⌉
+
1
,
wherein p ┌L/2┐ represents the middle precoding vector, and └x┘ is a largest integer equal to or less than x.
15 . The first communication node according to claim 10 , wherein in the transmitting of the data to the second communication node, the at least one processor causes the first communication node to perform:
transmitting a pilot signal to the second communication node; receiving, from the second communication node, feedback information including information of a precoding matrix for a channel state between the first communication node and the second communication node; confirming the precoding matrix included in a codebook using the feedback information; and transmitting the data to the second communication node by performing beamforming based on the precoding matrix included in the codebook.Join the waitlist — get patent alerts
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